High severity · published Jul 29, 2026
CVE-2026-67215
cJSON JSON Patch copy/add Uncontrolled Recursion Stack Exhaustion
7.5
CVSS
0.7%
EPSS
No
On KEV
Description
cJSON through 1.7.19 is vulnerable to uncontrolled recursion leading to stack exhaustion when an untrusted RFC 6902 JSON Patch is applied via cJSONUtils_ApplyPatches() or cJSONUtils_ApplyPatchesCaseSensitive(). A patch containing add and copy operations grafts duplicated subtrees to amplify document depth beyond the parser's nesting limit: cJSON_Delete() recurses with no depth bound, and the cJSON_Duplicate() guard CJSON_CIRCULAR_LIMIT is set to 10000, ten times the parser's 1000-level nesting limit and high enough to overflow a default thread stack. An attacker who can supply the patch document can crash the process, resulting in denial of service.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.7% · higher than 53% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
CJ
cJSON · DaveGamble
through 1.7.19 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-67215
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-67215
Patch
https://github.com/DaveGamble/cJSON/blob/v1.7.19/cJSON.c#L253-L261
Patch
https://github.com/DaveGamble/cJSON/blob/v1.7.19/cJSON_Utils.c#L906-L940
Exploit
https://joshua.hu/cjson-json-parser-cve-vulnerabilities
Third Party Advisory
https://www.vulncheck.com/advisories/cjson-json-patch-copy-add-uncontrolled-recursion-stack-exhaustion
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